Related Experiment Video
Updated: Oct 7, 2026

3D Ultrasound Imaging: Fast and Cost-effective Morphometry of Musculoskeletal Tissue
Published on: November 27, 2017
Active force-length relationship of human lower-leg muscles estimated from morphological data: a comparison of
C W Spoor1, J L van Leeuwen, W J van der Meulen
1Department of Anatomy, University of Leiden, The Netherlands.
Abstract:
Muscle fibre lengths, pennation angles, and sarcomere lengths were measured (the latter by a diffraction technique) for each of the muscles of three embalmed lower-leg specimens. From these data and filament lengths from Walker & Schrodt (1973), the optimum fibre lengths were determined. Relationships between length and active force (at full activation) of the lower-leg muscles were calculated by use of (i) a unipennate muscle model, (ii) a bipennate model, and (iii) bipennate models in which the cosine of the pennation angle is approximated as length independent. It is concluded that the first two models are equally useful and that the use of the last models is discouraged in case of strongly pennated muscles. Non-uniformity of fibre parameters within one muscle appears to have little effect on the force-length relationship.
Related Concept Videos
Bones of the Lower Limb: Femur and Patella
Bones of the Lower Limb: Tibia and Fibula
Indeterminate Structure
Muscles that Move the Leg
Anterior Compartment
The quadriceps femoris, the most visible muscle of the anterior compartment, is integral for leg extension and thigh flexion. It is formed by merging four distinct muscles — the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris. The quadriceps tendon, a shared tendon of the four quadriceps muscles, is affixed to...
Muscles of the Leg that Move the Foot and Toes
Anterior Compartment
The anterior compartment includes muscles that contribute to the dorsiflexion of the foot. This compartment houses the tibialis anterior, extensor hallucis longus, and extensor digitorum longus muscles.

